1. Field of the Invention
The present invention relates to a multilayer high frequency electronic component, in particular, a multilayer high frequency electronic component in which an inductor is integrated therein, similar to an LC filter which is built into a mobile communication device.
2. Description of the Related Art
A conventional multilayer LC filter 61 shown FIG. 9 includes a signal line 80 arranged to function as an inductor L and defined by only one conductor pattern on the surface of a ceramic sheet 74. Capacitor conductors 83, 84 are provided on the surface of a ceramic sheet 76, while a common capacitor conductor 82 is provided on the surface of a ceramic sheet 77. The capacitor conductor 83 and the common capacitor conductor 82 constitute an input side capacitor C1 across the ceramic sheet 76. Similarly, the capacitor conductor 84 and the common capacitor conductor 82 also constitute an output side capacitor C2 across the ceramic sheet 76. In addition, ground conductors 81, 85 are provided on the surface of the ceramic sheets 72, 78. The signal line 80 and the conductors 81-85 are disposed on the surface of the ceramic sheets 72, 74, 76-78 by a method such as a thick film printing method.
After the ceramic green sheets 71-78 of the above-mentioned constitution are laminated and press-fitted, they are integratedly baked to form a laminated body. An input external electrode 62 and an output external electrode 63 are disposed on right and left end portions of the laminated body, respectively. The external input electrode 62 is connected to the capacitor conductor 83 while the external output outer electrode 63 is connected to the capacitor conductor 84. An external relay electrode 64 and external ground outer electrodes 65, 66 are disposed on the side surface on the distal side of the laminated body. The external relay electrode 64 is connected to the signal line 80 and the common capacitor conductor 82. The external ground electrode 65 is connected to the signal line 80 and the ground conductors 81, 85, while the external ground electrode 66 is connected to the ground conductors 81, 85. External ground electrodes 67, 68, 69 are disposed on the side surface on the proximal side of the laminated body. The external ground electrodes 67, 68, 69 are connected to the ground conductors 81, 85, respectively.
In the conventional multilayer LC filter 61 having the above-described constitution, there is a problem that no satisfactory Q characteristic of the inductor can be achieved because of the reasons described below.
(1) The film thickness of the signal line 80 arranged to function as the inductor L is as thin as 20-30 .mu.m at a maximum film thickness portion even though the thick film printing method capable of increasing the film thickness is used. Thus, the resistance component of the signal line 80 is large, and an excellent Q characteristic of the inductor cannot be obtained.
(2) When the high frequency current flows in the signal line 80, the flow of the high frequency current is concentrated at an edge portion of the signal line 80 due to the skin effect. Thus, the sectional area of the signal line 80 is reduced, and the resistance component of the signal line 80 is further increased.